Process for the removal of printing plates

ABSTRACT

Printing plates are removed from the surface of a printing plate cylinder by initially releasing the leading edge of the plate from a clamping assembly and allowing the plate&#39;s resiliency to let it separate slightly from the surface of the cylinder. This leading edge of the plate is guided into a storage compartment and continued rotation of the plate cylinder causes the plate to be fully inserted into the storage compartment. The leading edge of the plate is released after contact with a last ink application roller and before the entrance to the storage compartment.

FIELD OF THE INVENTION

The invention relates to a process and a device for the removal ofprinting plates from plate cylinders of rotary printing presses.

DESCRIPTION OF THE PRIOR ART

A feed and removal device for a printing press is known from EP 02 14549 B1, wherein, during the removal of the printing plates from theplate cylinder, the printing plates are held by means of guide rollers,which can be placed against the circumference of the plate cylinder, andby associated actuation devices. This is disadvantageous in that theseadjustable plate pressure rollers and their actuating devices not onlymake access to the plate cylinder more difficult, but also require anadditional outlay in technical devices. Further than that, a largeportion of the circumference of the plate cylinder is occupied by theabove mentioned devices, so that only a limited number of cylinders, forexample ink application rollers, can be present at the plate cylinder,otherwise the plate cylinder must have larger dimensions. In connectionwith above mentioned EP 02 14 549 B1 it is furthermore disadvantageousthat a driven guide roller is employed during the plate feeding processand is in contact with the sensitive side of the printing plate. Thiscan lead to damage of this sensitive side, particularly if the feedspeed of the printing plate is adjustable in the way this is handled inaccordance with EP 02 14 549 B1 by accelerating and subsequent slowingdown of the plate feed.

During the plate retraction or plate removal process it is furthermoredisadvantageous that here too, a driving guide roller is employed whichis in contact with the sensitive side of the printing plate, so thatdamage to it cannot be counted out, which is an obstacle to the reuse ofthe printing plate.

SUMMARY OF THE INVENTION

It is the object of the invention to produce a process for the removalof printing plates from a plate cylinder of a rotary printing press anda device for executing the process.

The following advantages in particular are achieved by means of theinvention.

Driven conveying members for the printing plates, such as drive rollers,do not come into contact with the ink-carrying sensitive side of theprinting plate, so that the printing plate is not damaged duringchanging and therefore nothing stands in the way of reusing it. Becauseof the simultaneous use of the ink application rollers as an auxiliarydrive or conveyance for the printing plates to be removed, the inkapplication rollers have a multiple function. Further than that it ispossible to place a plurality of ink application rollers against theplate cylinder. Because of the arrangement of air conduits and byblowing on the sensitive side of the printing plate in the storagecompartment it is assured that this side does not come into contact withthe storage compartment and thus a gentle removal of the printing platestakes place.

BRIEF DESCRIPTION OF THE DRAWINGS

The associated drawings show in:

FIGS. 1 to 4, respectively schematic side views of a feed and removaldevice for printing plates in various positions of the plate cylinder;

FIG. 5, a partial, enlarged representation of a portion of FIG. 3;

FIG. 6, a representation of the plate front edge of a printing plate inthe plate alignment unit;

FIG. 7, a control device and a control computer;

FIG. 8, a flow chart for the removal of a printing plate from the platecylinder;

FIG. 9, a flow chart for feeding a printing plate to the plate cylinder;and,

FIG. 10, a section taken along line X--X in accordance with FIG. 6 andwith an enlarged representation of a detail of the apparatus inaccordance with FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The structure of a device in accordance with the invention in thedifferent plate cylinder positions is shown in schematic representationsin FIGS. 1 to 4. A rotary printing press has several printing units 1,for example four printing units, each of which contains, among otherthings, a plate cylinder 2, a rubber blanket 3 and a counterpressurecylinder 4. Furthermore, a number of ink application rollers 6, 7, 8 aswell as a moisture and ink application roller 9 are arranged at thecircumference of the plate cylinder 2 and can be placed against theplate cylinder 2 by known means, not shown. Distributing rollers, notfurther identified, are furthermore connected with the rollers 6 to 9.The cylinders 2 to 4 and the rollers 6 to 9 are directly or indirectlyseated in side frames. A removal and feed device 12 for printing plates13, 14 is provided at an access side 11 to the cylinders 2, 3, 4 of theprinting unit 1. This device 12 consists of a housing which isapproximately as wide as a printing plate and has two storagecompartments 16, 17. Viewed in section, the housing has a slightcurvature so that an upper portion of the housing initially is orientedalmost vertically and the cross section of a lower portion is widenedapproximately trapezoidally and extends in the direction toward theplate cylinder 2. In this case a front wall 18 of the housing extendspast a pressure roller 19.

The pressure roller 19 is disposed slightly below the plate cylinder 2and can be placed against the plate cylinder 2 by means of a workcylinder 21 fixed on the front wall and of an angle lever 22, alsoseated on the front wall. In comparison with a printing plate 13, 14,the pressure roller 19 has a soft surface, for example made of rubber orplastic. A rear wall 23 of the housing extends as far as shortly infront of the last ink application roller 8 above a contact line 24 atwhich the ink application roller 8 touches the plate cylinder 2 or theprinting plate 13 on the plate cylinder 2, so that the rear wall 23 hasa larger radius of curvature than the front wall 18. An intermediatewall 26 is disposed between the front wall 18 and the rear wall 23 andseparates the two storage compartments 16, 17 from each other. However,the intermediate wall 26 is shorter than the walls 18, 23 and terminatesin front of a conveying device, identified by 27 as a whole, forprinting plates 13, 14. Respectively one air conduit 28, 29 extendsparallel with the respective wall 18, 23 and outside of the compartments16, 17 and is connected via a number of openings 31 with the respectivestorage compartment 16, 17. The air conduits 28, 29 are bounded by airconduit walls 32, 33 which are placed at a distance from the front wall18 or the back wall 23. The air conduits 28, 29 are fed by a compressedair supply installation, not shown. The air conduit wall 32, 33, thefront and rear walls 18, 23 and the intermediate wall 26 arerespectively connected by front walls 34 which are symbolicallyindicated by two brackets, - partially shown in FIG. 1. These frontwalls 34 extend from the upper part, which runs in the verticaldirection, to the end of the trapezoidally widened part of the removaland feed device 12 on the periphery of the plate cylinder 2.

The conveying device 27 consists of a driven conveying roller 36, asshown in FIG. 5, which is fixed on the front side, and which, in theaxial direction, has comb-shaped recesses on its periphery. Theserecesses are engaged by fingers 37 attached at approximately rightangles at the lower end of the intermediate wall 26. This conveyingroller 36 is driven by a motor, for example a torque-adjustablepneumatic motor. A pressure roller 38, which can be placed against thelower end of the storage compartment 17 for printing plates 13 to beremoved, is disposed on one side of this conveying roller 36 and isconnected via an angle lever 39, seated fixed in the rear wall, with thepiston rod of a work cylinder 41, also seated fixed in the rear wall. Apressure roller 42, which can be placed against the lower end of thestorage compartment 16 for printing plates 14 to be fed in, is disposedon the other side of this conveying roller 36 and is connected via anangle lever, seated fixed in the front wall, with the piston rod of awork cylinder 44, also seated fixed in the front wall. The pressurerollers 38, 42 have a soft, resilient surface, for example made ofrubber.

A guide bar 46, as may also be seen in FIG. 10, which is embodiedtrapezoidally in cross section and extending in the axial direction ofthe plate cylinder 2, is located below the conveying device 27 in thetrapezoidally widened part. The underside and the top of the guide bar46 are each concavely formed and matched to the radius of the platecylinder 2 or the conveying roller 36. Below the conveying device 27, afirst front face 47 of the guide bar 46 constitutes the boundary of thestorage compartment 16 for plate feeding in respect to the front wall18. Below the conveying device 27, a second front face 48 of the guidebar 46 constitutes the boundary of the storage compartment 17 for plateremoval in respect to the rear wall 23, or the end of the rear wall 23pointing in the direction toward the plate cylinder 2 is disposed atsuch a distance from the contact line 24 of the last ink applicationroller 8, viewed in the direction of rotation, with the plate cylinder2, forming an entrance 49, that the printing plate 13 to be removed canbe placed into this entrance 49 and can be further conveyed through thestorage compartment 17. Viewed from the plate cylinder 2, this entrance49 tapers in the direction toward the conveying device 27 and thus iswedge-shaped in cross section.

An alignment unit for the front edge of a plate, identified as a wholeby 52, is located between the conveying device 27 and the pressureroller 19. The alignment unit 52 for the front edge of a plate consistsof a rotatable shaft 53, seated in the front walls 34 of the removal andfeed device 12, with at least two alignment pins or indexing stops 51extending from the periphery of this shaft 53 in the radial directionand corresponding with alignment devices 54 at the front edges of theprinting plates 13, 14, as seen in FIG. 6. The shaft 53 is connected viaa rocker 50 through a hinge with the piston rod of a work cylinder 55,fixed on the front wall and hingedly seated.

For repair and maintenance purposes of the printing unit 1, the removaland feed device 12 can be upwardly pivoted around two bearings 56, 57fixed on the frame by means of a rocker 59 hinged on the front wall 18and of a two-armed lever 60 hinged on the front wall 18. The two-armedlever 60 is connected with its first lever arm 58 via a bearing fixed onthe frame and with its second lever arm 61 via a hinge with the pistonrod of a work cylinder 62 fixed on the frame.

In a depression 63, the plate cylinder 2 has a plate clamping device 64and a plate clamping and gripping device 66. Such a device is known fromDE 36 04 071 C2. Open- and closeable clamping flaps or gripper devices67, 68, which each cooperate with a gripper support surface 70, as seenin FIG. 10 are disposed on the plate clamping devices 64, 66 of theplate cylinder 2 near the periphery of the plate cylinder 2. In thiscase the gripper device 67 is connected with the front edge, i.e. thestart of the print, and the gripper device 68 always with the rear edge,i.e. the end of the print, of the respective printing plate 13, 14.Actuating means provided for actuating the gripper device 67, 68 or theplate clamping device 64, 66 are supplied with work medium via a rotaryinput (not shown) on a journal of the plate cylinder 2. However, it isalso possible to provide devices which supply the plate cylinder withwork medium through its front face or jacket surface. The actuatingmeans can be embodied as hydraulic, pneumatic or electrical units. As arule, the gripper device 67, 68 is designed as a gripper support strip.

In operation, assume that it is intended to change the printing plate atthe end of the current print order. For this purpose, as may be seen inFIG. 1, with the application rollers 6 to 9 placed against it, the platecylinder 2 moves with the front edge 69 of the printing plate 13 pastthe application rollers 9, 6, 7 to a contact line 24 between the lastapplication roller 8, viewed in the production rotating direction of theplate cylinder 2 (counterclockwise), and the plate cylinder 2, with theprinting plate 13 located in between. After the printing plate frontedge 69 has passed the contact line 24, the gripper device 67 opens and,because of its inherent tension, the printing plate front edge 69springs against the lower end 71 of the rear wall 23, so that startingat the contact line 24 the printing plate front edge 69 takes up an atleast tangential position in relation to the plate cylinder 2 (FIG. 1).In this way the printing plate front edge 69 moves into the tapering gap49. As will be described extensively later, a fresh printing plate 14can already be in the standby position at this time. Because of thecontinued counterclockwise rotation of the plate cylinder 2 in theproduction direction, the printing plate front edge 69 passes throughthe curved lower portion of the storage compartment 17 because of thefrictional connection with the application rollers 6 to 9, in the courseof which the pressure roller 38 of the conveying device 27 located inthe lower part of the removal and feed device 12 is shut off and the airconduits 28, 29 are permanently charged with compressed air, so that thesensitive side of the printing plate 13, 14 is always distanced from thefront wall 18 or the rear wall 23 of the removal and feed device 12, asmay be seen in FIG. 2.

At this time the fresh printing plate 14 is fed with its printing platefront edge 72 to the plate cylinder 2 and fastened thereon.

Because of the continuing rotation of the plate cylinder 2 in theproduction rotation direction, the trailing end of the printing plate 13reaches the contact line 24 between the last application roller 8 andthe plate cylinder 2 with the end of the printing plate 13 disposedbetween them. The gripper device 68 opens and with its softly resilientcover the pressure roller 38 pushes the printing plate 13 against thedriven conveying roller 36, so that the printing plate 13 continues tobe conveyed in the vertical direction to the outlet of the removal andfeed device 12, as depicted in FIG. 3. The application rollers 6 to 9can also be shut off.

At this time the printing plate 14 is further attached by rotating theplate cylinder 2.

While the plate cylinder 2 continues to turn in the production rotationdirection, the printing plate end of the printing plate 13, because ofthe conveying movement of the conveying device 27, reaches the fingers37 on which the printing plate 13 is now placed in readiness forremoval, as is shown in FIG. 4. The fresh printing plate 14 nowsimultaneously rests with its plate trailing end on the plate cylinder 2and is clamped by plate trailing end gripper 68.

Alternatively to the process step described in connection with FIG. 1,the start of the plate removal from the plate cylinder 2 can also takeplace in such a way that after reaching a contact line 73 locatedbetween the circumference of the moisture application roller 9 and thecircumference of the plate cylinder 2, all application rollers 6 to 9resting against the plate cylinder 2 are turned off by the plate frontedge 69, i.e. by known means they are moved back a few millimeters.Simultaneously therewith the gripper bar 67 opens, so that the printingplate 13 relaxes and its front edge 69 rests loosely against theapplication rollers 6 to 9, so that the conveyance of the printing plate13 to the storage compartment 17 takes place in an interlocking andfrictionally connected manner by means of the gripper bar 68.

The plate feed of a fresh printing plate 14 to the plate cylinder 2 isdescribed in more detail in what follows. With the pressure roller 42 ofthe conveying device 27 not in contact, the printing plate front edge 72of the printing plate 14 to be fed in is inserted into the storagecompartment 16 of the removal and feed device 12 and with its alignmentslits 54 located at the plate front edge, as seen in FIG. 6, it engagesthe alignment pins 51 located on the shaft 53 and projecting into thelower portion of the storage compartment 16, by means of which thealignment of the printing plate 14 takes place. Thus, the printing plate14 is located in the standby position on the plate alignment unit 52, asshown in FIG. 1. While the opened leading edge gripper bar 67 of theplate cylinder 2 approaches the lower end of the storage compartment 16,the shaft 53 is turned by 90° so that the alignment pins come out ofengagement with the alignment slits 54 at the plate front edge 72 of theprinting plate 14. Simultaneously therewith the pressure roller 42,which is provided with a softly resilient cover, is pushed against theprinting plate 14 and thus against the driven, counterclockwise rotatingconveying roller 36 of the conveying device 27. The pressure roller 42and the conveying roller 36 turn with a circumferential speed which is1.1 to 1.2 times the circumferential speed of the plate cylinder 2, sothat the aligned printing plate 14 is fed to the plate cylinder 2 at anaccelerated speed and moves with the alignment slits 54 against thestops of alignment pins 51 which are disposed on the plate cylinder 2,but in particular on the plate clamping device 64 located in thecylinder depression 63, as shown in FIG. 10. Subsequently, the plateleading edge gripper device 67 closes and holds the printing plate frontedge 72 in an interlocking and frictionally connected manner. Thepressure roller 19, provided with a softly resilient cover, is placedagainst the plate cylinder 2 or against the printing plate 14 locatedbetween them (FIG. 2). The plate cylinder 2 now continues to turn in theproduction rotation direction and the pressure roller 42 pressingagainst the plate cylinder 2 is pivoted away and thus brought into therest position (FIG. 3). Because of the continued turning of the platecylinder 2, the printing plate 13 to be removed leaves the platecylinder 2 and the plate trailing edge gripper bar 68, which was openedby this, can grip the trailing end of the printing plate 14 in aninterlocking and frictionally connected manner. The pressure roller 19is shut off. Plate transfer is now completed (FIG. 4).

Alternatively with the process step described in connection with FIG. 2,the feeding of the plate to the plate cylinder can also take place inthat a printing plate 14 provided with alignment devices 54 on its platefront edge 72 is guided from the storage compartment 16 in the directionof the plate cylinder 2 as far as the alignment unit 52 for the frontedge of a plate, is subsequently aligned there and is maintained in thestandby position. Subsequently, the plate cylinder 2 interrupts itsrotating movement and the conveying device 27, consisting of thepressure roller 42 and the driven conveying roller 36, conveys theprinting plate 14 in a tangential direction to a gripper support surface70 on the plate cylinder 2, as seen in FIG. 10 on which indexing stops51 are disposed.

FIG. 7 shows the representation of a control device and a controlcomputer 74 for use with the present invention. The control computer 74receives its information on the one hand from a position transmitter 76for monitoring the resting of the printing plate 13, 14 with itsadjustment devices against the stop 51 on the plate cylinder 2. On theother hand, the control computer 74 receives information by means of aposition transmitter 77 disposed on the plate cylinder 2. The controlcomputer 74 is furthermore connected with a number of electromagneticvalves 78, which, upon a command to change printing plates, are switchedin the correct sequence as a function of the positions of the platecylinder 2 and in connection with suitable software and supply the workcylinders with a working medium, for example compressed air from apressure source 79. Also, all electrical drive elements, for example thedrive 81 for the printing unit and thus also for the plate cylinder 2,are controlled by the control computer 74. The software of the controlcomputer 74 operates in accordance with a flow chart that is shown inFIGS. 8 and 9, so that the steps 101 to 107 or 201 to 216, as will nowbe discussed are performed automatically in sequence.

FIG. 8 shows the flow chart for unclamping and removing the printingplate 13 from the plate cylinder 2 or placement into the storagecompartment 17 of the removal and feed device 12. An interrogation 102of the safety conditions is performed by actuating a starting trigger101, to determine, for example, whether the removal and feed device 12is in the operating position. The device 12 could also be situated inits upwardly pivoted position remote from the cylinder by means of themanually operable work cylinder 62. Appropriate sensors are thereuponactivated. Among other things, the interrogation whether the storagecompartment 17 is free is performed. If these conditions are not met, atrouble signal 103 is generated. When all safety conditions have beenmet, a start warning signal 104 is generated. The plate cylinder 2 isturned at creep speed into the plate cylinder position A (PC Position A)105 in FIG. 1 by means of a renewed actuation of the starting trigger101. In the plate cylinder position A the front edge 69 of the printingplate 13 at the contact line 24 is just in contact with the applicationroller 8 and the plate cylinder 2. After the plate front edge 69 haspassed the contact line 24, the plate clamping device 64 is released ina step 106, the gripper bar 67 of the plate clamping device 64 is openedand the pressure roller 38 is moved out by the work cylinder 41.Thereafter, following continued turning of the plate cylinder 2, the endof the pressure plate 13 reaches the contact line 24 between the lastapplication roller 8 and the plate cylinder 2 (PC Position 2) in a step107 (FIG. 3). In a subsequent step 108, the gripper bar 68 of the plateclamping and gripping device 66 opens and the pressure roller 38 in thestorage compartment 17 is brought into contact. The printing plate 13lies ready for removal on the fingers 37.

FIG. 9 shows a flow chart in accordance with which the control computer74 operates in connection with the other position indicators (forexample the angle of rotation transmitter 77) so that the printing plate14 is brought to the plate cylinder 2. An interrogation 202 of thesafety conditions is performed by actuating a starting trigger 201 forexample to determine whether the removal and feed device 12 is in theoperating position. Appropriate sensors are thereupon activated. If allconditions are not met, a trouble signal 203 is generated. When allsafety conditions have been met, a start warning signal 204 isgenerated. Renewed actuation of the starting trigger 201 activates thedrive 81 of the plate cylinder. A following interrogation 205 relates tothe presence of a fresh printing plate 14 in the storage compartment 16,wherein the alignment devices 54 of the printing plate front edge 72 ofthe printing plate 14 interlockingly receive the stops or alignment pins51. A trouble signal 206 is generated if the printing plate 14 ismissing. While the plate cylinder 2 approaches, with its opened gripperdevice 67, a cylinder position C (FIG. 2) at the lower end of thestorage compartment 16, the alignment unit 52 is shut off in a step 207by means of the actuation of the work cylinder 55 and simultaneously thepressure roller 42 is pushed in the direction toward the rotatingconveying roller 36 by the actuation of the work cylinder 44. In asubsequent step 208, the plate cylinder 2 is turned into a position C(FIG. 2), so that the printing plate 14 fed to the plate cylinder 2 atan accelerated speed. In a further step 209, another check is madewhether the gripper bar 67 is still open, and in a step 210 a check ismade whether the printing plate front edge 72 of the aligned printingplate 14 rests against the stops 51 on the plate cylinder 2. Theposition transmitter 76 and the angle of rotation transmitter 77 areswitched on. A trouble signal is generated in case the printing platefront edge 72 is not in contact or not in correct contact. Subsequently,the gripper device 67 is closed in a step 211 and the printing platefront edge 72 of the printing plate 14 is maintained interlockingly andin a frictionally connected manner and the pressure roller 19 is pivotedagainst the periphery of the plate cylinder 2 by the work cylinder 21.The pressure roller 38 is shut off in a further step 212 by actuatingthe work cylinder 41. Following a further counterclockwise rotation ofthe plate cylinder 2 in the production direction, a plate cylinderposition D (FIG. 4) is attained in a following step 213, wherein the endof the printing plate 14 rests on the plate cylinder 2 and issubsequently maintained in a frictionally connected manner by thegripper bar 68 in a step 214. The printing plate 14 is clamped. In astep 215 the pressure roller 19 is shut off by actuation of the workcylinder 21. The plate change operation is terminated. Following this atermination signal 216 is generated.

The work cylinders 21, 41, 44, 55, 62 are embodied as double-actingpneumatic work cylinders, whose inlet and outlet connector forcompressed air are not shown. The plate clamping device 64, located inthe cylinder depression 63, for fastening the printing plate front edge69, 72 can also be embodied as a combined plate clamping and grippingdevice. The ink application roller 8 can also be embodied as a separateroller which, for example, can perform the function of a reversingroller and can be separately actuable, i.e. can be placed against theplate cylinder 2 separately from the ink application rollers 6, 7, 9.

FIG. 10 shows a cross-section taken along line X--X of FIG. 6 with anenlarged detail representation in connection with FIG. 2. Starting froman axis of rotation 82 of the plate cylinder 2, with this axis ofrotation constituting the center of the circle, an outer circle 83 withthe radius r₁ defines the circumference of the plate cylinder 2 with itsgenerated area. A further, inner circle 84 has a radius r₂ which extendsfrom the axis of rotation 82 of the plate cylinder 2 and almost reachesthe gripper support surface 70. The radius r₂ is less than the radiusr₁.

On its end close to the plate cylinder 2 the storage compartment 16 hasa compartment end 86, which extends tangentially to a circle concentricto circle 83 or 84, and whose radius lies between the radii r₁ and r₂.The compartment end 86 extends tangentially to the plate cylinder 2 inthe III. quadrant of a right-angled coordinate system relative to theplate cylinder cross section. On its end close to the plate cylinder,the storage compartment 17 has a compartment end 87 which extendstangentially to a circle concentric to circle 83 or 84, and whose radiuslies between the radii r₁ and r₂. The compartment end 87 extendstangentially to the plate cylinder 2 in the II. quadrant of aright-angled coordinate system (FIG. 1). The compartment ends 86, 87 arerespectively placed opposite each other in the area of two adjoiningquadrants II and III. However, they can also be placed opposite eachother in adjoining quadrants I or IV or I and II.

The process can also be employed in an advantageous manner for printingplates which are beveled on one or both ends. A clamping device inaccordance with German Patent Application P 43 26 248.1, which isincorporated herein by reference, is the basis for the furtherdescription. A slotted rotatable clamping spindle is disclosed in thispatent application, with this rotatable clamping spindle being disposedin a depression of a plate cylinder. The front end of the beveledprinting plate is suspended in a suspension edge of the plate cylinderwhich is parallel with the cylinder axis. In this case, the trailing endof the printing plate is also beveled and is inserted into the linearslot of the clamping spindle. This clamping spindle can be selectivelyplaced into every angle of rotation position and stopped in it.

The beveled printing plate front end of the printing plate is lifted atthe latest when the suspended, beveled printing plate front edge passesthe first--viewed in the production rotation direction--ink applicationroller 9 of the plurality of ink application rollers 9, 6, 7, 8 whichhave been lifted off the plate cylinder. By means of this, a free spaceis provided between the printing plate on the plate cylinder 2 and theink application rollers 6 to 9. In this case, the ink applicationrollers are only used to gently guide the loosened printing plate 13.The ink application rollers can turn during the removal of the printingplate, but they can also stand still. If the printing plate front edgepreferably has, as already mentioned, reached the area of the guidingink application rollers 6 to 9, the clamping spindle is slightly turnedin the direction of unclamping of the printing plate. The printing platetrailing edge is unclamped and is pushed slightly in the directiontoward the printing plate front edge, since the beveled trailing end ofthe printing plate is in the slot of the clamping spindle. In theprocess, the beveled line of the printing plate leading end is supportedeither on the interior wall of the suspension bar or on the surface ofthe beveled plate front edge facing toward the clamping spindle. Theprinting plate trailing end preferably remains in this position("printing plate loosened") until, in the suspended state, the beveledfront edge of the printing plate has reached the area of the last guideroller, in this case the ink application roller 8. Now the clampingspindle makes a further turn in the direction of unclamping of theprinting plate and pushes the printing plate, by pushing the printingplate trailing end, which is still in the slot, in the direction towardthe printing plate front edge. After a sufficient length of displacementpath of the printing plate trailing end and thus of the printing plate,the beveled leading end of the printing plate automatically rises out ofthe suspension bar because of its resilient properties and with itsentire edge springs past the jacket of the plate cylinder 2. However,since the springiness is limited by the last roller, for example the inkapplication roller 8, it is possible to direct the printing plate frontedge in such a way, that it is pushed into an entrance 49 of a printingplate removal device 38, 36, 17 because of the rotational movement ofthe plate cylinder 2.

No later than at the passage of the printing plate leading end past thelast roller 8, the beveled trailing edge of the printing plate isautomatically moved out of the slot in the clamping spindle by theresilient properties of the printing plate and in this way comescompletely free of the clamping spindle.

The clamping spindle can be brought to any arbitrary position, forexample by means of the clamping spindle having teeth on itscircumference, into which the teeth of a toothed rack disposed below theclamping spindle can be displaced into any desired position by means ofan inflatable hose and maintained there. A corresponding turning of theclamping spindle takes place in accordance with the displacement of thetoothed rack. The tension of a pressure spring which acts on the toothedrack on the side opposite the air hose is used for clamping. If the airhose is not under pressure, this pressure spring moves the clampingspindle by means of the toothed rack into the direction of clamping theprinting plate.

To unhook the suspended printing plate front edge from the suspensionbar it would also be possible to provide pneumatically or electricallycontrolled lifters in the plate cylinder, which act on the end of thebeveled edge and in this way lift it in the direction toward the platecylinder circumference until the beveled front edge springs out of thesuspension bar because of its inherent resilience and the printing platefront edge is freed in this way.

We claim:
 1. A process for removing a clamped printing plate having afront edge and a trailing end from a rotating plate cylinder of a rotaryprinting press, in which said front edge and said trailing end of saidclamped printing plate are fastened on the plate cylinder, including thesteps of:passing said printing plate front edge of said printing plateon the plate cylinder, which is rotating in a first, productiondirection, past a last ink application roller of a number of inkapplication rollers; freeing said front edge of said clamped printingplate from a clamping device usable for holding said printing platefront edge on said plate cylinder; utilizing a restoring force inherentin said printing plate for moving said printing plate front edge awayfrom the plate cylinder; continuing rotating the plate cylinder in saidfirst, production direction; directing said front edge of said printingplate, immediately following a contact of said front edge with said lastink application roller, into an entrance of a storage compartmentadjoining a contact line between said plate cylinder and said last inkapplication roller; loosening said trailing end of said printing platefrom a trailing end clamping device on the plate cylinder; allowing saidtrailing end of said printing plate to leave the area of said last inkapplication roller; and subsequently gripping said printing plate with aconveying device and moving said printing plate into said storagecompartment.
 2. A process in accordance with claim 1, further includinglifting said number of ink application rollers off the plate cylinderand using said lifted ink application rollers as guides for the printingplate to be removed.
 3. A process for removing a clamped printing platehaving a front edge and a trailing end from a rotating plate cylinder ofa rotary printing press, in which said front edge and said trailing endof said clamped printing plate are fastened on the plate cylinder,including the steps of:unclamping said front edge of said printing platefrom a front edge clamping device on the plate cylinder no later thanduring the passage of said clamped front edge of said clamped printingplate past, as viewed in a first, production direction of rotation ofthe plate cylinder, a first one of a number of ink application rollers;disengaging said front edge of said printing plate from the platecylinder; allowing said front edge of said printing plate to be slightlylifted off the plate cylinder jacket by an inherent restoring force insaid printing plate; continuing to hold said printing plate trailing endin a device for gripping and clamping said printing plate trailing endin a "printing plate loosened" position on the plate cylinder until saidprinting plate front edge has reached an area of a last one of saidnumber of ink application rollers; subsequently continuing rotating theplate cylinder, with said now loosened printing plate in said first,production direction; pushing said printing plate leading edge, by therotation of the plate cylinder and by moving said printing plate frontedge out of its said front edge clamping device because of said inherentrestoring force acting on said front edge off the plate cylinder; and;pushing said printing plate front edge into an entrance of a printingplate removal device positioned immediately adjoining the plate cylinderand placing said printing plate in a storage compartment in saidprinting plate removal device.
 4. A process in accordance with claim 3,further including completely releasing said printing plate trailing endfrom said device for gripping and clamping said printing plate trailingend no later than the passing of said printing plate trailing end pastsaid last one of said ink application rollers and the reaching of atleast the level of a jacket surface of the plate cylinder by saidprinting plate trailing end.
 5. A process in accordance with claim 3including providing a suspension edge on the plate cylinder which isparallel with a cylinder axis of rotation and using said suspension edgeas a device for holding said printing plate front edge on the platecylinder.
 6. A process in accordance with claim 3 further includingproviding a rotatable clamping shaft with an axis-parallel slot toreceive the printing plate trailing end on the plate cylinder, andselectably positioning said clamping shaft in at least the positions"receive printing plate trailing end", "clamp printing plate trailingend", "loosen printing plate trailing end" and "release printing platetrailing end".
 7. A process in accordance with claim 6, furtherincluding disposing said rotatable clamping shaft capable of beingbrought from said position "loosen printing plate trailing end" intosaid position "release printing plate trailing end", where saidrotatable clamping shaft may be fixed against rotation relative to theplate cylinder and arrestable in said "release printing plate trailingend" position.